This core will provide Biophysical based assessments for CHAIN investigators. Both state-of-the-art Bioimaging, including quantitative magnetic resonance imaging (MRI), MR spectroscopy (MRS) and single photon emission computed tomography (SPECT), and Electrophysiological methods, including patch clamping and extracellular analysis synaptic activity. Two 7-Tesla small animal MRl/S systems will provide quantitative neuroimaging and/or superparamagnetic iron oxide (SPIO) labeled cell tracking on rodent models of HlV-1 associated neurodegenerative disorder (HAND). The bioimaging core methods also include quantitative mapping of blood-brain barrier permeability, quantitative arterial spin labeled perfusion mapping, and quantitative proton MRS (^H MRS). The electrophysiology equipment and expertise will allow investigators access to state-of-the-art in vitro and in vivo approaches for studying how immune deficiency virus, viral products, cytokines, and cytotoxins, as well as genetic over- or under-expression of these elements alter molecular, cellular and synaptic physiology of neurons and brain regions believed to be involved in neuroAIDS. The techniques in the Core as a whole will also support developmental therapeutic studies relevant to microglial activation in HAD. The results obtained from this core will have direct applicability for determining the mechanisms and monitoring the course of HIV infection in its chronic stage. Our overriding goal is to assist CHAIN Pis and other researchers interested in neuroAIDS in determining and characterizing changes of CNS function as they develop in the various in vitro and in vivo models of neuroAIDS, and in exploring therapeutic potentials aiming at ameliorating or reversing such functional changes.